Irish in action:
Paul Dunne: -6 F
Padraig Harrington: -3 F
Darren Clarke: -1 thru 13
Graeme McDowell: E F
Shane Lowry: +1 F
Paul Dunne
Paul Dunne enjoyed another round to remember at St Andrews after carding a second consecutive 69 to move on to six under par for the tournament.
The Greystones native leads the hunt for the Silver Medal - which is awarded to the leading amateur - and is only three shots of Danny Willett's clubhouse lead.
It was a case of deja vu for Dunne, who registered four birdies and a lone bogey just as he had done in his opening round.
Having birdied the par-four ninth, the 22-year-old made back-to-back birdies on 14 and 15.
A bogey followed on the very next hole, but Dunne regained his composure to birdie the 18th.
Padraig Harrington
Three-time major winner Padraig Harrington's impressive iron play helped him to a round of 69.
Harrington bogeyed the second hole of his round on Friday before carding a birdie on the seventh hole. The 43-year-old enjoyed a fine back nine, racking up birdies on 13, 14 and 18 to finish three under for the day and the tournament.
Despite a good round, Harrington was realistic regarding his chances of adding to his major haul: "I've won two of them already, so it's not going to be life-changing or anything like that, but it would be nice to get into contention coming down the stretch and perform.
"We'll see what happens but, no matter what, I'm going to need a big weekend. I'm way behind. If I was leading the tournament I'd want beautiful conditions but I want everything thrown at us to give me chance to catch up."
Graeme McDowell
Graeme McDowell recorded a bogey on the fourth hole of his second round, but birdies on seven, 13 and 14 took him to two under before a double bogey at 17 left him even for the tournament overall.
McDowell's form had been on an upward curve heading into the Open, but it has been a challenging year for him after falling 40 places in the world rankings.
Darren Clarke
A run of pars started day two for Darren Clarke, but birdies at seven and eight took him to one under. In what is his 24th appearance in the Open, Clarke continued a string of pars to keep him on course to make the cut. He will Finish his second round on Saturday.
Shane Lowry
Shane Lowry carded nine pars in the first nine holes on Friday before a birdie and a bogey on 10 and 11 left him one over for the tournament.
The Offaly man's first round on Thursday was blighted by a quadruple-bogey on the 17th. An error from the tee cost Lowry as his drive went out of bounds and he found more trouble again before escaping with an eight.